Do you struggle to make your cellular energy unit engaging for students? I have, too!

Photosynthesis and cellular respiration are abstract concepts and many students struggle with them. Rather than just drilling them on molecular pathways and chemical equations, I’ve always tried to incorporate labs and activities to bring these concepts to life. I’ve seen some other photosynthesis and respiration labs, but they can be tricky and often frustrating for students. Instead, in planning my cellular energy unit, I’ve relied on some tried-and-true labs that are easy and inexpensive.

Photosynthesis Lab: Observing Stomata

This lab is more of a plant anatomy investigation, but it lends itself well to a discussion of photosynthesis, too. Students can use inexpensive materials (clear nail polish, clear tape, and a leaf) to make a microscope slide that allows them to observe the stomata of the leaf. The stomata are responsible for the gas exchanges required by the photosynthesis and cellular respiration processes. The guard cells on either side of the stoma opening are regulated by turgor pressure, so this is a great link between the concept of osmosis and photosynthesis. I usually do a quick discussion or exit ticket so students can explain which gases enter and leave through the stoma and how the available water regulates this gas exchange. Quick and easy, but it will amaze your students! You can see a video demonstration of this photosynthesis lab on my YouTube channel.

Cellular Respiration Lab: “Barf” Bags

Barf bags are arguably one of my favorite activities during the first half of the Biology course.

These are unbelievably simple I promise your students will remember them for years to come. By adding cereal, yeast, and warm water to a zipper bag, your students can see fermentation at work- all the way up to the point at which it pops! Although I don’t use formal lab reports often, there are a lot of variables that can be changed in this lab if you’d like to make it a true student-directed lab. The type of cereal, amount of each ingredient, and temperature of water all play a role in the amount of carbon dioxide being produced. You can even grab my Barf Bag Lab for free in my Teachers Pay Teachers store.

Photosynthesis Lab: Leaf Chromatography

Leaf chromatography is an experiment that allows students to see the pigments hidden inside a leaf. The primary pigment inside a leaf is chlorophyll, which is responsible for the production of food through photosynthesis. When leaves change color in the autumn, the chlorophyll breaks down revealing the other pigments that remain. Photosynthesis is often taught in the autumn, which makes this lab perfect so students can teach their friends and families about seasonal color changes. If this experiment fits well into your course, you can easily find instructions for leaf chromatography online.

Virtual labs for photosynthesis and cellular respiration are a little harder to find, but here’s a great photosynthesis lab simulation from Biology Corner. I hope these photosynthesis and cellular respiration lab ideas get your students moving and engaged with these tough concepts!